This invention relates to arc welding apparatus and to an improvement in filler wire feeding that does not increase the bulk size of the welding torch.
While performing gas tungsten arc welding (GTAW) in which a gap exists between the objects to be welded, a filler material is introduced into the weld puddle. Previously this had been performed manually by the welder, feeding a short length wire into the vicinity of the weld puddle. With the advent of automated welding equipment, continuous wire feeders are now being used. They consist of an additional flexible hose used to deliver the wire, a mounting bracket external to the torch, and a short length of semi-flexible tubing from the bracket to the vicinity of the weld puddle. The torch already has a water supply line and return line, one of which supplies current for the weld process, and a cover gas supply line, and the additional filler wire hose needlessly adds to the problems associated with routing the hoses to the torch. More importantly the separate bracket adds an unacceptable bulkiness to the torch. With this type configuration, many welds cannot be performed due to mechanical interference between parts and the torch. There is also a greater possibility of mechanical damage to the torch, parts, or fixtures.
The improved method of introducing the welding wire to the weld puddle and compact GTAW torch are disclosed in the context of a robotic welding torch with an integral vision sensor to directly view the weld puddle and structured light pattern. Several commonly-assigned copending applications cover various features of the integrated optics. One of these, Ser. No. 528,753, filed Sept. 1, 1983, A. W. Case, Jr. and D. C. Peroutky, "Gas Metal Arc Welding Torch with Vision System", describes an integral wire feed contact tube screwed into a dog leg on the torch body and has a completely separate inert gas system.